Render generic rollout projections in frontstage

[huangruiteng]

Summary

• add a generic public-safe rollout projection bundle for the overnight Accept Harbor reducer wrapper in run ledger upsert #746-Fix profile-scoped side-agent handoff routing #775 PR batch
• render wall-clock timeline, PR nodes, relationship edges, hover details, rollout sequence, mapping layers, flow signals, and attention hotspots in frontstage
• extend route/browser smokes to cover the projection renderer and public/private boundary behavior

Validation

• python3 examples/frontstage-rollout-projections-fixture-smoke.py
• npm --prefix apps/dashboard run smoke:frontstage-route
• npm --prefix apps/dashboard run build
• npm --prefix apps/dashboard run smoke:frontstage-browser
• git diff --check origin/main...HEAD
• loopx check on touched public/dashboard files (clean except pre-existing loopx-meta duplicate-index warning)

Owner gate

• Owner approved the frontstage preview and requested merge after the generic rollout projection review gate todo_db42dac13138.

[huangruiteng]

Owner approval received in the active Codex thread: approve and merge.

Local validation before merge:

• python3 examples/frontstage-rollout-projections-fixture-smoke.py
• npm --prefix apps/dashboard run smoke:frontstage-route
• npm --prefix apps/dashboard run build
• npm --prefix apps/dashboard run smoke:frontstage-browser
• git diff --check origin/main...HEAD
• loopx check on touched public/dashboard files (clean except pre-existing loopx-meta duplicate-index warning)

I will merge after the GitHub Frontstage Pages check finishes green.